The present invention relates to a container with collapsible sidewalls and in particular to a container which retains an internal volume after collapse of the sidewalls.
Containers used for handling and shipping materials are well known and found in a range of sizes and uses. Materials-handling containers have found increasing use with the introduction of "just in time" production methods. Such containers are often produced in a foldable or collapsible form in order that return shipping of the containers will require a minimum of space. This type of container is generally described in U.S. Pat. No. 4,674,647 issued Jun. 23, 1987, to Gyenge, et al. Previous devices have typically attempted to provide the collapsed container in a form which is as compact as possible, with no substantial internal spaces or volumes in the collapsed form. This configuration has presented difficulties when the containers are used in connection with package or dunnage because once the container is collapsed, there is no room for containing such packing material or dunnage and thus the packing material or dunnage must either be disposed of or must separately packaged for return in a different container.
Typical previous devices have used sidewalls which are dimensioned such that when they are collapsed they do not extend beyond the perimeter defined by the container base. Some such containers have sidewalls dimensioned so that they do not extend beyond a midline of the container base. In either case, the vertical extend (in the uncollapsed configuration) of the sidewall is determined by the size of the base. Accordingly, previous devices did not provide containers with a range of sidewalls heights, independent of the base size.